3-D printers coming for medical apps

SAN JOSE, Calif. – Medical device companies could someday use 3-D printers to quickly make an array of products from custom implants to valves and ultra fine micro-needle arrays for drug delivery. But the technology is not quite ready for prime time, said an expert in the field.

A handful of current 3-D printing techniques all hold promise and pitfalls. The systems are typically much faster and simpler than conventional manufacturing techniques, but they are still relatively imprecise, expensive and lack bio-compatibility, said Roger Narayan, professor of biomedical engineering at the University of North Carolina at Chapel Hill

“There’s a lot of interest in honing these techniques for medical apps,” said Narayan in a talk at the BioMeDevices Forum here. “We are getting to the point where surgical implants can be made with rapid prototyping—some dentists are already using it for temporary crowns,” he said.

In the near term, some forms of 3-D printers could be used to create molds or casts for a wide variety of small implants, valves and disposable devices. They could also be an alternative for making micro-needle arrays where traditional processes are seen as a bottleneck, Narayan said.

“It’s really about lower cost systems, wider choice of input materials and improved bio-compatibility” for these applications, he said.

Long term, 3-D printing holds promise to make combination devices that mix living cells with other materials to create implants that are less frequently rejected by the human body. But that will require a generation of more cell-friendly 3-D printers.

Narayan has conducted 3-D printing experiments using an argon fluoride excimer laser, one of many approaches that can use cells as an input media. But currently, “the scaling is not there, throughput is too low,” he said.

Meanwhile, some stereo lithography systems using liquids are creating features that range from 75 to 10 microns. A relatively new two-photon polymerization approach has created features measuring as little as 100 nm. “So you can get to truly small scale structures nowadays,” he said.

Roger Narayan laid out current 3-D printing approaches and their medical uses.